Vacations to the Jersey shore as a child gave the Green Bay Packers' defensive coordinator a glimpse of the life. His father, a high school football coach in suburban Philadelphia, took a briefcase to the beach, settled a chair into the sand and went to work.

"I do the same ... But it's a backpack. I'm a little more with the times," Pettine said.

The lessons passed on by dad stay with him to this day.

Mike Pettine Sr., who died in Feburary 2017, was one of the most successful coaches in Pennsylvania prep history. Pettine, 51, is coaching again in the NFL after being hired by head coach Mike McCarthy to oversee the Packers defense. He returned after largely staying out of football following a two-year stint as head coach of the Cleveland Browns, serving as a consultant with Seattle in 2017.

"I thought it was normal for everybody else's dad to carry a briefcase on to the beach," Pettine said after a recent Packers practice. "He always had (football) on his mind, it was always there. If it wasn't direct, it was always kind of lurking. He always had pen and paper close, if an idea popped into his head."

Those ideas often worked.

The elder Pettine won 326 games at Central Bucks West High School and four state titles. He retired in 1999 following a third consecutive unbeaten season.

Pettine played for his father and later served as an assistant coach. He ended up across the field from his father, too, after taking the head coaching job at rival North Penn — matchups that often made Philadelphia-area headlines. Pettine took over a team that went from hovering at about .500 to challenging his father's team for state supremacy.

The elder Pettine was a Philadelphia Eagles fan, though he had no qualms about rooting for whatever team that his son was working for as he climbed the NFL coaching ladder. Pettine's first stop in the pros came in 2002 as an assistant with the Baltimore Ravens.

Dad would serve as a consultant. Pettine would send him DVDs to view film. Later, he could watch on an iPad.

"A lot of times he would start the conversations with, 'I know I'm just a high school football coach, however ...,'" Pettine recounted. "He would give us 10 things and they were all dead on. ... He just had a great eye for the game."

A high school coach can sometimes resemble a drill sergeant on the job. The style in the NFL is a bit different. For Pettine, it's about creating an environment where players and coaches work together.

But he admired the way his father adjusted to players in a career that started in the 1960s.

"I thought his strength was his ability to adapt, where he goes from an age of kids where they never questioned authority and by the time he finished that had essentially flipped," he said.

"And I think you have to be able to adapt, and I feel the same way when you're working with NFL players," he said. "I just think it's important to know your audience, understand that you're working with the, trying to help them be successful, which in turn will help you be successful."

Team film sessions at CB West with Pettine Sr., on Mondays after Friday games stick out, too.

"You would never know (they won) if you sat in on those film sessions — you would think they lost by 30 when they had won by 30," Pettine said. "But I'm a big believer in there's no better teaching tool than seeing it on film. You paint a picture, you show a guy, 'Hey, this is how it's supposed to look.'"

It was a way that his father held his players accountable, which is also important to Pettine.

"My dad said, 'Stop the projector, turn on the lights. Quick, stand up and explain to your teammates what you were just doing.' Nobody wanted that to happen," Pettine said. "And that's something I've always believed, being honest with your players, being direct, that's by far the best way to go about things."